package com.wc.blue_bridge_test.base.T71;

import java.math.BigInteger;
import java.util.Scanner;

/**
 * @Author congge
 * @Date 2023/12/27 22:09
 * @description 阶乘计算
 * https://lx.lanqiao.cn/problem.page?gpid=T71###
 */
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        BigInteger ans = new BigInteger("1");
        while (n > 0) {
            ans = ans.multiply(new BigInteger(String.valueOf(n)));
            n--;
        }
        System.out.println(ans);
    }
}
